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Postural Sway Is Associated with Disability Status and Cerebellar Dysfunction in People with Multiple Sclerosis: A Preliminary Study

James McLoughlin, MSc; Christopher Barr, PhD; Maria Crotty, PhD; Stephen R. Lord, DSc; Daina L. Sturnieks, PhD

From Flinders University, South Australia, Australia (JM, CB, MC); and Neuroscience Research Australia (SRL, DLS) and School of Public Health and Community Medicine (JM, SRL, DLS), University of New South Wales, Sydney, Australia.

Background:

The aims of this study were to a) examine postural sway in eyes open (EO) and eyes closed (EC) conditions in people with MS with moderate levels of disability and healthy controls (HC), and b) examine relationships between postural sway and total Expanded Disability Status Scale (EDSS) scores, functional system subscores, and clinical measures of strength and spasticity within the MS group.

Methods:

Thirty-four people with moderate MS and 10 matched healthy controls completed measures of postural sway with eyes open (EO) and eyes closed (EC), knee extension and ankle dorsiflexion isometric strength, EDSS total score and subscores, and spasticity levels.

Results:

MS participants swayed significantly more with eyes open and closed and had reduced knee extension and ankle dorsiflexion strength compared with healthy controls (P < .001). Within the MS group, increased sway was associated with higher total EDSS scores and cerebellar function subscores, while increased sway ratio (EC/EO) was associated with reduced sensory function subscores. Postural sway was not significantly associated with strength or spasticity.

Conclusions:

People with MS sway more and are significantly weaker than healthy controls. Cerebellar dysfunction was identified as the EDSS domain most strongly associated with increased sway, with sensory loss associated with a relatively greater dependence on vision for balance control. These findings suggest that exercise interventions targeting sensory integration and cerebellar ataxia may be beneficial for enhancing balance control in people with MS.